" He opened his eyes to the real world. Everything was moving with the slowness of a broken pict screen. Around him the Exiles of the Thousand Sons stood in the ruins of Tizca. Above him lights swelled within the storm cloud as the shells fell from the heavens.
He reached up to his chest. The cracked back of a jade scarab found his fingers. His mind was suddenly empty, suddenly still. He felt the stone of the jade scarab. It was warm to his touch, just as it had been before, when Prospero had died under the axes of the Wolves. He knew that perhaps he alone of his brothers had kept that broken memento of their first flight from Prospero. Then it had unified the Legion, as Magnus had given the last of his power to save those who survived.
Now, Ahriman did not need it to draw his brothers together. They were him and he was them. But the scarab mattered. It was not a connection to his brothers. It was a connection to the past, a connection to that first journey across space and time, a connection to the bridge that Magnus had created between Prospero and their refuge in the Eye. A key to opening that way again.
You cannot step in the same river twice, he thought, the ancient words rising unbidden to his mind. Above him tears of flame fell from the frozen sky.
For it is not the same river.
He gripped the scarab and closed his eyes.
And you are not the same man. "

― John French , Ahriman: Unchanged (Ahriman #3)